try:
    l = list(map(int,input().split()))
    flag=True
    for i in range(len(l)-1):
        for j in range(i+1,len(l)-1):
            if flag:
                if not l[i]>=l[j]:
                    l[i],l[j]=l[j],l[i]
                flag = not flag
                break
            else:
                if not l[j]>=l[i]:
                    l[i],l[j]=l[j],l[i]
                flag = not flag
                break
    res=""
    for i in l:
        res += str(i)+" "
    print(res.strip())
except:
    print("[]")